Active matrix type liquid crystal display device having first pixel signal lines wider than second pixel signal lines

ABSTRACT

A display device with a plurality of gate signal lines extended in the first direction; a plurality of drain signal lines extended in the second direction; a plurality of pixel regions in a state that each pixel region includes a switching device, a pixel electrode which is connected with the drain signal line and a counter electrode. The counter electrode is formed with respect to the pixel electrode by way of an insulation film and is formed every pixel. The pixels include first pixels and second pixels, wherein only the first pixels have a counter voltage signal line which extends in the first direction, and the counter voltage signal line is connected with the counter electrodes in the first pixels. Further, the counter electrodes of the first pixels and the counter electrodes of the second pixels are electrically connected with each other using conductive stride over the gate signal line.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of nonprovisional U.S. application Ser.No. 11/038,232 filed on Jan. 21, 2005 now U.S. Pat. No. 7,453,539 .Priority is claimed based on U.S. application Ser. No. 11/038,232 filedon Jan. 21, 2005, which claims the priority of Japanese Application2004-019905 filed on Jan. 28, 2004, all of which is incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display device and a driving methodthereof.

2. Description of the Related Art

With respect to a liquid crystal display device which constitutes oneexample of a display device, there has been known a type of liquidcrystal display device which forms a pixel electrode and a counterelectrode in each pixel region on a surface of one substrate which facesa liquid crystal side in an opposed manner.

This type of liquid crystal display device is required to supply asignal which becomes the reference to the counter electrodes and hence,the liquid crystal display device is configured such that it isnecessary to arrange counter voltage signal lines which constitutesignal lines for the signal together with gate signal lines and drainsignal lines which become necessary to drive the respective pixels (seeU.S. Pat. No. 6,462,799).

In this case, it is necessary to arrange the drain signal lines suchthat the drain signal lines intersect the counter voltage signal linesand hence, a drawback attributed to the increase of a so-called crossingcapacitance has been pointed out.

On the other hand, there has been known a technique in U.S. Pat. No.6,646,706 in which the counter voltage signal line is formed in commonwith respect to the neighboring respective pixels so as to reduce thenumber of counter voltage signal lines.

SUMMARY OF THE INVENTION

However, when the counter voltage signal line is formed in common withrespect to the neighboring respective pixels as mentioned above, thecounter electrodes are inevitably configured to be connected with onlythe above-mentioned counter voltage signal line and hence, theconnection of these counter electrodes with counter electrodes of pixelsto which other counter voltage signal line is provided cannot beestablished.

It is because that to largely alleviate the time constant of the signalsupplied to the counter voltage signal line, it is desirable toelectrically connect the counter electrode with the electrodes of thepixels which are arranged in the left-and-right directions as well as inthe up-and-down directions.

Further, so long as the counter voltage signal line is formed in commonwith respect to the neighboring respective pixels, due to therestriction that the counter voltage signal line is arranged every oneother line with respect to a pixel group formed of pixels which arearranged in parallel in the extending direction of the counter voltagesignal line, it is difficult to arrange the counter voltage signal lineevery two other lines or every three other lines.

The present invention has been made under such circumstances. It is anadvantage of the present invention to provide a liquid crystal displaydevice which is configured such that each counter electrode can beelectrically connected with counter electrodes of respective pixelsarranged at the left and right sides as well as at the upper and lowersides of the counter electrode.

Further, another advantage of the present invention is to provide aliquid crystal display device which can arrange counter voltage signallines which supply a signal to counter electrodes every one other lineor every two or more other lines with respect to a pixel group ofrespective pixels which are arranged in parallel in the extendingdirection of the counter voltage signal lines.

To briefly explain the summary of the typical inventions among theinventions disclosed in this specification, they are as follows.

(1)

The liquid crystal display device according to the present inventionincludes, for example, first and second substrates with a liquid crystallayer therebetween, a plurality of gate signal lines which are formed onthe first substrate and are extended in the first direction, a pluralityof drain signal lines which are formed on the first substrate and areextended in the second direction, and a plurality of pixel regions whichare formed on the first substrate in a state that each pixel regionincludes a switching device, a pixel electrode which is connected withthe drain signal line and a counter electrode, wherein the counterelectrode is formed on the substrate side with respect to the pixelelectrode by way of an insulation film and is formed every pixel,

the pixels include first pixels and second pixels, wherein only thefirst pixels out of the first pixels and the second pixels have acounter voltage signal line which extends in the first direction, andthe counter voltage signal line is connected with the counter electrodesin the inside of the first pixels, and

the counter electrodes of the first pixels and the counter electrodes ofthe second pixels are electrically connected with each other usingconductive layers which are formed in a state that the conductive layersstride over the gate signal lines.

(2)

The liquid crystal display device according to the present invention is,for example, on the premise of the constitution (1), characterized inthat the first pixels and the second pixels are alternately arranged inthe second direction.

(3)

The liquid crystal display device according to the present invention is,for example, on the premise of the constitution (1), characterized inthat the extending direction of the pixel electrodes or slits formed inthe pixel electrodes assumes the direction which makes an acute anglewith respect to the gate signal lines.

(4)

The liquid crystal display device according to the present invention is,for example, on the premise of the constitution (1), characterized inthat the number of pixel electrodes in the first pixel or the number ofslits formed in the pixel electrode is smaller than the number of pixelelectrodes in the second pixel or the number of slits formed in thepixel electrode.

(5)

The liquid crystal display device according to the present invention is,for example, on the premise of the constitution (1), characterized inthat a distance of a pair of gate signal lines which are arranged aboveand below and close to the counter electrodes of the first pixels is setlarger than a distance of gate signal lines which are arranged above andbelow and close to the counter electrodes of the second pixels.

(6)

The liquid crystal display device according to the present invention is,for example, on the premise of the constitution (5), characterized inthat the number of pixel electrodes in the first pixel or the number ofslits formed in the pixel electrode is equal to the number of pixelelectrodes in the second pixel or the number of slits formed in thepixel electrode.

(7)

The liquid crystal display device according to the present invention is,for example, on the premise of the constitution (5), characterized inthat some of the gate signal lines have bent portions at portionsthereof which extend over a display region, and the distance between thegate signal line and another neighboring gate signal line is set to afixed value by the bent portions.

(8)

The liquid crystal display device according to the present invention is,for example, on the premise of the constitution (1), characterized inthat the polarity of a drain signal supplied to the drain signal linesdiffers between a range from the first pixel to a portion of the secondpixel immediately before the next first pixel and a range from the nextfirst pixel to a portion of the second pixel immediately before thestill next first pixel.

(9)

The liquid crystal display device according to the present inventionincludes, for example, first and second substrates with a liquid crystallayer therebetween, a plurality of gate signal lines which are formed onthe first substrate and are extended in the first direction, a pluralityof drain signal lines which are formed on the first substrate and areextended in the second direction, and a plurality of pixel regions whichare formed on the first substrate in a state that each pixel regionincludes a switching device, a pixel electrode which is connected withthe drain signal line and a counter electrode, wherein the counterelectrode is formed on the substrate side with respect to the pixelelectrode by way of an insulation film and is formed every pixel,

the pixels include first pixels and second pixels, wherein only thefirst pixels out of the first pixels and the second pixels have acounter voltage signal line which extends in the first direction, andthe counter voltage signal line is connected with the counter electrodesin the inside of the first pixels,

the counter electrodes of the first pixels and the counter electrodes ofthe second pixels are electrically connected with each other usingconductive layers which are formed in a state that the conductive layersstride over the gate signal lines, and

the drain signal line has a width thereof set larger in the second pixelthan in the first pixel.

(10)

The liquid crystal display device according to the present invention is,for example, on the premise of the constitution (9), characterized inthat the first pixels and the second pixels are alternately arranged inthe second direction.

(11)

The liquid crystal display device according to the present invention is,for example, on the premise of the constitution (9), characterized inthat the extending direction of the pixel electrodes or slits formed inthe pixel electrodes assumes the direction which makes an acute anglewith respect to the gate signal lines.

(12)

The liquid crystal display device according to the present invention is,for example, on the premise of the constitution (9), characterized inthat the number of pixel electrodes in the first pixel or the number ofslits formed in the pixel electrode is smaller than the number of pixelelectrodes in the second pixel or the number of slits formed in thepixel electrode.

(13)

The liquid crystal display device according to the present invention is,for example, on the premise of the constitution (9), characterized inthat the polarity of a drain signal supplied to the drain signal linesdiffers between a range from the first pixel to a portion of the secondpixel immediately before the next first pixel and a range from the nextfirst pixel to a portion of the second pixel immediately before thestill next first pixel.

(14)

The driving method of a display device according to the presentinvention is, for example, characterized in that the display deviceincludes first pixels which have a counter voltage signal line andsecond pixels which have no counter voltage signal line, the firstpixels and the second pixels are periodically arranged in the extendingdirection of drain signal lines, a period ranges from one first pixel tothe second pixel immediately before the next first pixel, and a signalapplied to the drain signal lines has a polarity thereof changed everyperiod.

(15)

The driving method of a display device according to the presentinvention is, for example, on the premise of the constitution (14), thepolarity is a polarity with respect to a potential of the countervoltage signal line.

Here, the present invention is not limited to the above-mentionedconstitution and various modifications can be made without departingfrom the technical concept of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A, FIG. 1B, FIG. 1C and FIG. 1D are constitutional views showingone embodiment of the constitution of a pixel of a liquid crystaldisplay device according to the present invention;

FIG. 2A is a constitutional view showing one embodiment of theconstitution of the pixel of the liquid crystal display device accordingto the present invention, and FIG. 2B is a constitutional view showing adriving method of the liquid crystal display device;

FIG. 3 is a constitutional view showing another embodiment of theconstitution of the pixel of the liquid crystal display device accordingto the present invention;

FIG. 4 is a constitutional view showing another embodiment of theconstitution of the pixel of the liquid crystal display device accordingto the present invention;

FIG. 5 is a constitutional view showing another embodiment of theconstitution of the pixel of the liquid crystal display device accordingto the present invention;

FIG. 6 is a constitutional view showing another embodiment of theconstitution of the pixel of the liquid crystal display device accordingto the present invention;

FIG. 7 is a circuit diagram showing one embodiment of the liquid crystaldisplay device according to the present invention;

FIG. 8 is a view showing one embodiment of the constitution of thevicinity of a terminal portion of a gate signal line of the liquidcrystal display device according to the present invention;

FIG. 9 is a view showing another embodiment of the constitution of thevicinity of a terminal portion of a gate signal line of the liquidcrystal display device according to the present invention; and

FIG. 10 is a view showing another embodiment of the constitution of thevicinity of a terminal portion of a gate signal line of the liquidcrystal display device according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the liquid crystal display device of thepresent invention are explained in conjunction with drawings.

Embodiment 1

FIG. 7 is a schematic plan view showing one embodiment of the whole of aliquid crystal display device according to the present invention. Thedrawing shows a circuit which is formed on a liquid-crystal-side surfaceof one transparent substrate SUB1 out of respective transparentsubstrates which are arranged to face each other by way of liquidcrystal.

On a front surface of the transparent substrate SUB1, respective regionswhich are surrounded by gate signal lines GL which extend in the xdirection and are arranged in parallel in the y direction and drainsignal lines DL which extend in the y direction and are arranged inparallel in the x direction are defined as pixel regions and a mass ofthese pixel regions constitute a liquid crystal display part AR.

Although the detailed structure of the pixel region is described later,out of these respective pixel regions, with respect to pixel groups eachof which is constituted of the pixel regions arranged in parallel in thex direction, counter voltage signal lines CL are formed to run in theinside of the pixel groups which are arranged every one other in the ydirection.

The counter voltage signal lines CL are signal lines for supplying avoltage signal which becomes the reference with respect to a videosignal supplied to the pixel electrodes PX in the inside of therespective pixels to the counter electrodes CT in the inside of thepixels. Originally, the counter voltage signal lines CL are formed torun in the respective pixel groups each of which is arranged in parallelin the x direction, in this embodiment, as described above, the countervoltage signal lines CL are formed to run in the inside of the pixelgroups which are arranged every one other in the y direction. Thisarrangement is provided for reducing an intersecting capacity of thedrain signal lines DL with respect to the counter voltage signal linesCL.

To the above-mentioned respective gate signal lines GL, a scanningsignal is sequentially supplied from a gate driver G-Drv by scanning,while a video signal is supplied to the respective drain signal lines DLfrom the drain driver D-Drv in conformity with the timing of scanning.

Each pixel region is provided with a thin film transistor TFT which isturned on with the supply of the scanning signal from the gate signalline GL and a pixel electrode PX to which the video signal is suppliedfrom the drain signal line DL via the thin film transistor TFT. Thevideo signal (voltage) which is supplied to the pixel electrode PXgenerates an electric field together with a counter voltage signal(voltage) supplied to the counter electrode CT and the opticalmodulation of the liquid crystal is controlled in response to theelectric field.

Here, the gate driver G-Drv and the drain driver D-Drv are configured tosupply the scanning signal and the video signal upon receiving thesignals from a power source circuit PS and a liquid crystal displaycontrol circuit TCON.

FIG. 1A is a plan view showing one embodiment of the constitution of thepixels and depicts the pixels by extracting 2×3 pieces of pixels out ofthe respective pixels arranged in a matrix array.

Further, respective cross-sectional views taken along lines A-A′, B-B′and C-C′ shown in FIG. 1A are respectively shown in FIG. 1B, FIG. 1C andFIG. 1D.

On the liquid-crystal-side surface of the transparent substrate SUB1,the gate signal lines GL which extend in the x direction and arearranged in parallel in the y direction are formed.

These respective gate signal lines GL are configured to surroundrectangular regions together with the drain signal lines DL describedlater and these regions constitute the pixel regions.

Here, in the inside of a region of the pixel which is positioned at thecenter of the drawing, the counter voltage signal line CL which extendsin the x direction is configured to be formed simultaneously with theformation of the respective gate signal lines GL, for example. In thiscase, the counter voltage signal line CL is formed to be arranged closethe gate signal line GL on one side (the lower side in the drawing) soas to prevent the counter voltage signal line CL from traversing thecenter of the pixel region. This provision is made to avoid thereduction of the so-called numerical aperture of the pixel.

The counter voltage signal line CL is not formed in the inside of thepixels which are positioned on the immediate upper side and theimmediate lower side with respect to the pixel in which the countervoltage signal line is formed. That is, as mentioned above, in therespective pixels which are arranged in the matrix array, the countervoltage signal lines CL are arranged in parallel every one other pixel,for example, in the extending direction of the drain signal lines DL.

The counter electrode CT is formed on the transparent substrate SUB1 ateach pixel region, wherein the counter electrode CT is formed of alight-transmitting conductive layer which is made of, for example, ITO(Indium Tin Oxide), ITZO (Indium Tin Zinc Oxide), IZO (Indium ZincOxide), SnO₂ (Tin Oxide) or In₂O₃(Indium Oxide), wherein the counterelectrode CT is formed on the whole area of the center portion excludinga trivial peripheral portion of the pixel region.

In this case, the counter electrode CT which is formed in the inside ofthe pixel in which the counter voltage signal line CL is arranged isdirectly overlapped to the counter voltage signal line CL and iselectrically connected with the counter voltage signal line CL. On theother hand, the counter electrodes CT which are formed in the inside ofthe pixels which are arranged immediately above and immediately belowthe above-mentioned pixel in the drawing are formed in an electricallyisolated state at this stage. However, as can be understood from theexplanation made later, these counter electrodes CT are configured toassume a state in which these counter electrodes CT are alsoelectrically connected with the counter voltage signal line CL.

On the surface of the transparent substrate SUB1 on which the gatesignal lines GL, the drain signal lines DL and the counter electrodes CTare formed, an insulation film GI which is made of SiN, for example, isformed in a state that the insulation film GI also covers the gatesignal lines GL and the like.

The insulation film GI has several functions including a function as aninterlayer insulation film with respect to the gate signal lines GL inthe regions where the drain signal lines DL described later are formedand a function as a gate insulation film in regions where the thin filmtransistors TFT are formed as described later.

Then, on a surface of the insulation film GI, semiconductor layers ASmade of amorphous Si, for example, are formed in a state that thesemiconductor layers AS are overlapped to portions of the gate signallines GL.

The semiconductor layer AS is a semiconductor layer of the thin filmtransistor TFT. By forming a drain electrode SD1 and a source electrodeSD2 on an upper surface of the thin film transistor TFT, it is possibleto constitute an MIS type transistor having the inversely staggeredstructure which uses a portion of the gate signal line as the gateelectrode.

Here, the drain electrodes SD1 and the source electrodes SD2 are formedsimultaneously with the formation of the drain signal lines DL.

That is, the drain signal lines DL which extend in the y direction andare arranged in the x direction are formed, the drain electrodes SD1 areformed by extending portions of the drain signal lines DL to uppersurfaces of the semiconductor layers AS, and the source electrodes SD2are formed in a spaced-apart manner from the drain electrodes SD1 by adistance corresponding to a channel length of the thin film transistorsTFT.

The source electrodes SD2 are electrically connected with the pixelelectrodes PX which are formed on an upper surface of a protective filmPAS explained hereinafter, wherein end portions of the source electrodesSD2 are slightly extended into the inside of the pixel regions andconstitute contact portions.

The protective film PAS is formed as a sequentially laminated body madeof an organic material and an inorganic material, for example, on theupper surface of the transparent substrate SUB1 in a state that theprotective film PAS also covers the thin film transistors TFT. Theprotective film PAS is provided for avoiding the direct contact of thethin film transistors TFT with the liquid crystal.

Then, in each pixel region, the pixel electrode PX is formed on an uppersurface of the protective film PAS, and the pixel electrode PX is formedof a light-transmitting conductive layer which is made of, for example,ITO (Indium Tin Oxide), ITZO (Indium Tin Zinc Oxide), IZO (Indium ZincOxide), SnO₂ (Tin Oxide) or In₂O₃ (Indium Oxide). The pixel electrode PXis constituted of an electrode group in which a plurality of strip-likeelectrodes which make an angle θ with respect to the gate signal linesGL are arranged in parallel in the extending direction of the drainsignal line DL.

Here, the respective electrodes of the electrode group are electricallyconnected with each other by a conductive layer made of the samematerial which is integrally formed with the electrode group in aperipheral portion of the pixel region.

Accordingly, the pixel electrode PX is formed in a pattern in which aplurality of slits which make an angle θ with respect to the gate signallines GL are formed in a conductive layer formed on the center portionof the pixel region except for the periphery thereof in the extendingdirection of the drain signal lines DL.

Further, the pixel electrode PX is, at a portion of a periphery thereof,connected with the source electrode SD2 of the thin film transistor TFTvia a through hole which is preliminarily formed in the protective filmPAS which is arranged below the pixel electrode PX.

Here, the panel-like pixel electrode PX in which the slits are formed isformed in a state that an outer profile thereof is displaced from anouter profile of the counter electrode CT and hence, a portion of theperipheral portion of the counter electrode CT has a portion whichprojects from the pixel electrode PX. The pixel electrode PX isconfigured to be electrically connected with the counter electrode CT ofthe neighboring another pixel (the neighboring pixel in the extendingdirection of the drain signal line DL) at such a projecting portion.

That is, in the respective pixels which are arranged close to each otherin the extending direction of the drain signal line DL, a conductivelayer CB is formed in a state that the conductive layer CB strides overa portion of the gate signal line GL, one end of the conductive layer CBon a lower-pixel side in the drawing, for example, with respect to thegate signal line GL is connected with the counter electrode CT of thepixel via the through hole which penetrates the protective film PAS andthe insulation film GI arranged below the pixel, while another end ofthe conductive layer CB on an upper-pixel side in the drawing withrespect to the gate signal line GL is connected with the counterelectrode CT of the pixel via the through hole which penetrates theprotective film PAS and the insulation film GI arranged below the pixel.

For each pixel, the conductive layer CB is provided on respective pixelsides which are respectively positioned at upper and lower portions inthe extending direction of the drain signal line DL. Due to such aconstitution, the counter electrodes CT of the respective pixels whichare arranged in parallel in the y direction are electrically connectedby the conductive layers CB and the counter voltage signal is suppliedto these respective counter electrodes CT through the counter voltagesignal lines CL which are intermittently arranged in the y direction.

Here, the conductive layers CB are made of the same material as thepixel electrodes PX and are configured to be formed simultaneously withthe formation of the pixel electrodes PX. This provision is made toavoid the increase of manufacturing man-hours.

In this case, the conductive layer CB is formed on the gate signal lineGL in a relatively largely spaced-apart manner from the thin filmtransistor TFT and a width of the conductive layer CB is also setrelatively small. This is because that each conductive layer CB isformed to stride over only one gate signal line GL and hence, even withthe above-mentioned width, the connection with each counter electrode CTcan be ensured without any drawbacks in terms of capacitance as well aselectrically.

Further, on the surface of the transparent substrate SUB1 on which thepixel electrodes PX and the conductive layers CB are formed, anorientation film AL is formed and the initial orientation direction ofthe molecules of liquid crystal which are directly brought into contactwith the orientation film AL can be defined by this orientation film AL.

Further, a transparent substrate SUB2 is arranged to face thetransparent substrate SUB1 in an opposed manner by way of the liquidcrystal LC. On a liquid-crystal-side surface of the transparentsubstrate SUB2, a black matrix BM is formed in a state that the blackmatrix BM covers the respective thin film transistors TFT and, at thesame time, defines the respective pixel regions. FIG. 1A depicts openingportions of the black matrix BM in an overlapped manner.

On the surface of the transparent substrate SUB2 on which the blackmatrix BM is formed, color filters CF are formed in a state that thecolor filters CF cover the openings formed in the black matrix BM. Thecolor filters CF are, for example, constituted of filters of respectivecolors consisting of red (R), green (G), blue (B), wherein, for example,the red filters are formed in common in each group of pixel regionswhich are arranged in parallel in the y direction, while the colorfilters having the arrangement of green (G), blue (B), red (R) . . . areformed in common in groups of pixel regions which are sequentiallyarranged close to the above-mentioned group of pixel regions in the xdirection.

Further, an orientation film is formed on the transparent substrate SUB2in a state that the orientation film also covers the color filters CF.The orientation film constitutes a film which is directly brought intocontact with the liquid crystal and defines the initial orientationdirection of the molecules of the liquid crystal.

The liquid crystal display device having such a constitution isconfigured such that the counter voltage signal lines CL are formedevery one other pixel in the y direction thus reducing the number ofcounter voltage signal lines CL. Further, the supply of the countervoltage signal to the counter electrodes CT of the pixels to which thecounter voltage signal line CL is not provided is performed by theconductive layers CB which are connected with the counter electrodes CTand the counter electrodes CT of the pixels to which the counter voltagesignal line CL is provided in a state that the conductive layers strideover the gate signal line GL.

Due to such a constitution, it is possible to reduce the intersectingcapacitance of the drain signal line DL with the counter voltage signalline CL without deteriorating the driving of the pixels.

Embodiment 2

FIG. 2A is an explanatory view showing another embodiment of the liquidcrystal display device according to the present invention. Although thedrawing shows the constitution which is substantially equal to theconstitution shown in FIG. 1, the driving method is modified so as toreduce the power consumption.

In general, so-called n-dot inversion driving (driving which inverts thepolarity of the video signal with respect to the counter electrode CTfor every n pieces of gate signal lines GL) can decrease the number ofthe inversion of the polarity of the video signal and hence, the powerconsumption can be reduced.

However, between the first pixel and the next pixel whose polarities areinverted, there arises the difference in the rise of the video signaland hence, there arises a drawback that a writing ratio of the initialpixel becomes worse than a writing ratio of the next pixel and hence,the brightness irregularities are liable to be easily generated.

Accordingly, by arranging the counter voltage signal line CLcorresponding to the initial pixel in the n-dot inversion, thedifference is generated in the stability of the common potential betweenthe first pixel and the succeeding pixels in the n-dot inversion so asto approximate the writing ratios to each other.

That is, by arranging the counter voltage signal line CL in the pixelwhich exhibits the poor writing ratio thus stabilizing the commonpotential, the writing ratio of the pixel can be enhanced.

Then, by providing no counter voltage signal line CL to other pixels, soas to lower the stability of the common potential of other pixels thanthe stability of the common potential of the preceding pixel, thewriting ratios can be lowered. Accordingly, the difference in thewriting ratio between the first pixel and next pixel in the n-dotinversion can be decreased and hence, it is possible to have anadvantageous effect that the reduction of the power consumption can berealized and the lowering of image quality (brightness irregularities)in such writing can be enhanced compared to the prior art.

In FIG. 2A, from the upper portion to the lower portion in the drawing,the pixel which is not provided with the counter voltage signal line CL,the pixel which is provided with the counter voltage signal line CL, andthe pixel which is not provided with the counter voltage signal line CLare sequentially arranged. These pixels are alternately arrangedhereinafter. Assuming the pixel in which the counter voltage signal lineCL is arranged as the pixel (1) and the pixel in which the countervoltage signal line CL is not arranged as the pixel (2), the pixel (1)and the pixel (2) are alternately arranged. When the scanning of thegate signal lines GL are sequentially performed from the upper side tothe lower side in the drawing, the video signal which is supplied to thepixel (1) and the pixel (2) assumes the positive polarity and,thereafter, the video signal which is supplied to the next pixel (1) andthe pixel (2) assumes the negative polarity. That is, the pixels aredriven such that the video signal is supplied to the pixels whilesequentially changing the polarity thereof.

FIG. 2B shows such a timing chart. Since the polarity of the signal ischanged over in the pixel (1), a change quantity of the potential of thevideo signal in the pixel (1) is more remarkable than the correspondingchange quantity of the potential of the video signal in the pixel (2).That is, in the pixel (1), the writing ratio of the TFT which exhibits avalue higher than the writing ratio of the TFT in the pixel (2) isrequired. Accordingly, by arranging the counter voltage signal line CLin the pixel (1), the difference between the voltages which are writtenin the pixel electrodes PX of the pixel (1) and the pixel (2) isreduced. Although the pixel (1) and the pixel (2) are alternatelyarranged in FIG. 2A, the pixels may be arranged with a unit which isconstituted of one pixel (1) and a plurality of pixels (2). In thiscase, it is desirable to drive the pixels such that the polarity ischanged over in accordance with the pixel unit consisting of the totalnumber of units. Due to such driving, it is possible to arrange thepixels (1) at portions where the polarity is changed over.

Embodiment 3

FIG. 3 is a plan view showing another embodiment of the pixel of theliquid crystal display device according to the present invention.Compared to the case shown in FIG. 1A, an area of the pixel region inwhich the counter voltage signal line CL is not formed is set largerthan an area of the pixel region in which the counter voltage signalline CL is formed. With respect to other constitution, the embodiment 3has the substantially same constitution as the embodiments 1 and 2.

Due to such a constitution, an area of the opening portion of the blackmatrix BM which substantially functions as the pixel in the pixel regionwhere the counter voltage signal line CL is not formed is set largerthan the corresponding area of the opening portion of the black matrixBM in the pixel region in which the counter voltage signal line CL isformed.

Further, due to such a constitution, the number of pixel electrodes PX(or the number of slits) which are viewed with naked eyes in the insideof the opening of the black matrix BM formed in the pixel region whichis not provided with the counter voltage signal line CL is set largerthan the corresponding number of pixel electrodes PX or the number ofslits in the pixel region which is provided with the counter voltagesignal line CL. To set the brightness per unit area in respective pixelsequal, it is necessary to set an interval of respective pixel electrodesPX which are constituted of a group of electrodes equal and hence, sucha constitution is adopted. This embodiment is provided for increasingthe so-called numerical aperture corresponding to a region which thecounter voltage signal line CL occupies in the pixel region which is notprovided with the counter voltage signal line CL.

Further, as the color filters CF, the green (G) filter is used in thepixel in which the counter voltage signal line CL is formed, while thered (R) filter is used in either one of the upper-side pixel and thelower-side pixel in the y direction in the drawing and the blue (B)filter is used in another pixel.

This is because that by allocating the color filter CF of green (G) tothe pixel which has the smaller numerical aperture compared to otherpixels, it is possible to favorably obtain the mixing of three primarycolors.

Here, with respect to the color filters CF, it is needless to say that,as usual, the color filters having the same color which are common inrespective pixels arranged along the y direction are used, while thecolor filters of red (R), green (G), blue (B), for example aresequentially arranged along the x direction.

Embodiment 4

FIG. 4 is a plan view showing another embodiment of the pixel of theliquid crystal display device according to the present invention.Compared to the case shown in FIG. 1A, an area (a width in the ydirection) of the pixel region in which the counter voltage signal lineCL is formed is set larger than an area of the pixel region in which thecounter voltage signal line CL is not formed. With respect to otherconstitution, the embodiment 4 has the substantially same constitutionas the embodiments 1 to 3.

Further, an area of the numerical aperture of the black matrix BM of thepixel region in which the counter voltage signal line CL is formed isset equal to an area of the numerical aperture of the black matrix BM ofthe pixel region in which the counter voltage signal line CL is notformed. This provision is provided for making the brightness of therespective pixels uniform.

Further, due to such a constitution, it is possible to have anadvantageous effect that the influence of the electric field from thedrain signal line DL to the counter electrode CT of the pixel arrangedclose to the drain signal line DL can be made uniform along the drainsignal line DL. That is, with respect to the pixel in which the countervoltage signal line CL is formed, although the drain signal line DLwhich is arranged close to the counter voltage signal line CL is formedwith a relatively long length, the counter electrode CT of the pixel isdirectly connected with the counter voltage signal line CL and hence iselectrically made stable.

On the other hand, to the counter electrode CT of the pixel in which thecounter voltage signal line CL is not formed, the signal is suppliedfrom the counter electrode CT of the pixel in which the counterelectrode signal line CL is formed via the conductive layer CB andhence, the signal is not electrically stable. However, the drain signalline DL which is arranged close to the pixel is made shortcorrespondingly and hence, the irregularities of the influence of theelectric field can be suppressed.

Embodiment 5

FIG. 5 is a plan view showing another embodiment of the pixel of theliquid crystal display device according to the present invention.Compared to the case shown in FIG. 4, in the pixel which is not providedwith the counter voltage signal line CL, the counter electrode CT iselectrically connected with the counter electrode CT of another pixelarranged close to the pixel in the x direction via a conductive layerBCT which intersects a portion of the drain signal line DL. Otherconstitutions are equal to the corresponding constitutions described inthe embodiment 1 to 4.

This embodiment is provided for making the potential of the counterelectrode CT of the pixel which is not provided with the counter voltagesignal line CL more stable.

Embodiment 6

FIG. 6 is a plan view showing another embodiment of the pixel of theliquid crystal display device according to the present invention.Compared with the case shown in FIG. 2, with respect to the pixel inwhich the counter voltage signal line CL is formed, a line width of thedrain signal line DL which is arranged close to the pixel is set small,while with respect to the pixel in which the counter voltage signal lineCL is not formed, a line width of the drain signal line DL which isarranged close to the pixel is set large. Other constitutions aresubstantially equal to the constitutions of the embodiments 1 to 5.

Here, in the case shown in FIG. 2, a spaced-apart distance of therespective gate signal lines GL is set equal and the pixel of theportion where the counter voltage signal line CL is formed is configuredto substantially narrow the pixel region in the y direction in thedrawing than other pixels due to a region that the counter voltagesignal line CL occupies.

To the contrary, in this embodiment, with respect to the pixel of theportion where the gate signal line GL is not formed, the substantialpixel region is narrowed in the x direction in the drawing by an amountcorresponding to the increase of the line width of the drain signal lineDL. Eventually, it is possible to make all of respective pixels have thesubstantially uniform area.

That is, the substantial area of the pixel which is determined based onthe opening area of the black matrix BM differs in an aspect ratiobetween the portion of the pixel where the counter voltage signal lineCL is formed and the portion of the pixel where the counter voltagesignal line CL is not formed. That is, the substantial area has thelarge lateral width and the small longitudinal width in the portion ofthe pixel where the counter voltage signal line CL is formed, while thesubstantial area has the small lateral width and the large longitudinalwidth in the portion of the pixel where the counter voltage signal lineCL is not formed. However, this embodiment can set these areas equal.

Further, by providing the portion which has the large width to the drainsignal line DL, it is possible to reduce an electric resistance value ofthe whole drain signal line DL and hence, the distortion of the waveformof the video signal which is supplied to the drain signal line DL can bereduced.

Embodiment 7

FIG. 8 is a view showing another embodiment of the liquid crystaldisplay device according to the present invention. Respective gatesignal lines GL which are formed on the liquid crystal display part ARextend and project from the liquid crystal display part AR and haveportions which reach terminals TM thereof. Here, symbol SL in FIG. 8indicates a sealing material which is formed between the transparentsubstrate SUB1 and another transparent substrate SUB2 which is arrangedto face the transparent substrate SUB1 in an opposed manner and sealsthe liquid crystal filled in the portion including the liquid crystaldisplay part AR.

FIG. 8 shows the constitution which is provided on a premise that adistance between a pair of gate signal lines GL which sandwich a groupof pixels extending in the x direction in which the counter voltagesignal line CL is formed is set wider than a distance between a pair ofgate signal lines GL which sandwich a group of pixels extending in the xdirection in which the counter voltage signal line CL is not formed.

In this case, portions of the respective gate signal lines GL have bentportions at portions which extend over the liquid crystal display partAR (inside the sealing material SL) and, after passing the bentportions, all gate signal lines GL have the equal interval and areconnected with the terminals TM.

The gate signal lines GL which include the bent portions are, forexample, selected every one other line and the extending portions areformed such that, after passing the bent portions, the extendingportions extend to the terminals TM while maintaining the equal intervalwith other neighboring gate signal lines GL.

Since the terminals TM are connected with pads of the gate driver G-Drvwhich is constituted of a semiconductor device, the spaced-apartdistance of the terminals TM is set equal. Due to such a constitution,the above-mentioned provision becomes necessary. Accordingly, it ispossible to have an advantageous effect that, in the inspection of thedisconnection of the gate signal lines GL or the like, it is possible touse an inspection device in which a spaced-apart distance between probeterminals is preliminarily set without modification.

FIG. 9 is, in the same manner as FIG. 8, shows a case in which adistance between a pair of gate signal lines GL which sandwich a groupof pixels extending in the x direction in which the counter voltagesignal line CL is formed is set wider than a distance between a pair ofgate signal lines GL which sandwich a group of pixels extending in the xdirection in which the counter voltage signal line CL is not formed,wherein the respective gate signal lines GL straightly and directlyextend over the liquid crystal display part AR and detection terminalsITM which detect disconnections or the like of the gate signal lines GLare provided between the liquid crystal display part AR and the sealingmaterial SL.

In this case, although the detection terminals ITM are positioned onlines of the gate signal lines GL every one other, remaining detectionterminals ITM are positioned to be slightly displaced from the gatesignal lines GL and wiring layers which connect the detection terminalsITM with the gate signal lines GL are provided.

This provision is made to cope with the situation that in spite of thefact that the respective gate signal lines GL are not arranged at anequal interval, it is necessary to arrange the detection terminals ITMat an equal interval.

Embodiment 8

FIG. 10 is a plan view showing another embodiment of the liquid crystaldisplay device according to the present invention and shows theconstitution in which respective gate signal lines GL which are formedon the liquid crystal display part AR extend and project from the liquidcrystal display part AR and the extending portions reach the terminalsTM.

Also in this case, a distance between a pair of gate signal lines GLwhich sandwich a group of pixels extending in the x direction in whichthe counter voltage signal line CL is formed is set wider than adistance between a pair of gate signal lines GL which sandwich a groupof pixels extending in the x direction in which the counter voltagesignal line CL is not formed.

Further, the respective gate signal lines GL which extend over theliquid crystal display part AR have an interval thereof narrowed suchthat the gate signal lines GL are gathered with each other in thevicinity of a sealing material SL and, thereafter, are connected withthe terminals TM which is formed outside the sealing material SL.

This provision is made to cope with the fact that the circuit which isconnected with the terminals is constituted of a semiconductor device,for example, and an interval of the bumps is set narrower than aninterval of the respective gate signal lines GL.

In this case, portions of the respective gate signal lines GL includebent portions at portions thereof which extend over the liquid crystaldisplay part AR (inside the sealing material SL) and extend to theterminals TM after passing the bent portions.

The gate signal lines GL which are provided with the bent portions areformed in a pattern that the gate signal lines GL are selected for everyone other, for example, and the extending portions after passing throughthe bent portions are gathered while maintaining the equal interval withother neighboring gate signal line GL.

The above-mentioned respective embodiments may be used in a single formor in combination. It is because that the advantageous effects of therespective embodiments can be obtained individually or synergistically.

Further, all of the above-mentioned embodiments are directed to the casein which the counter voltage signal lines CL are formed every one otherwith respect to the pixel groups each consisting of pixels arranged inparallel in the extending direction. However, it is needless to say thatthe present invention is not limited to such a constitution and thecounter voltage signal lines CL are formed every two other, every threeother or every number more than three other.

1. A liquid crystal display device comprising: first and secondsubstrates with a liquid crystal layer therebetween; a plurality of gatesignal lines which are formed on the first substrate and are extended inthe first direction; a plurality of drain signal lines which are formedon the first substrate and are extended in the second direction, eachone of the drain signal lines has a wide portion and a narrow portion;and a plurality of pixel regions which are formed on the first substratein a state that each pixel region includes a switching device, a pixelelectrode which is connected with the drain signal line and a counterelectrode, wherein the counter electrode is formed on the substrate sidewith respect to the pixel electrode by way of an insulation film and isformed every pixel, at least one of the pixel regions comprises firstpixels and second pixels, wherein only the first pixels have a countervoltage signal line which extends in the first direction, and isarranged only in the first pixels and the counter voltage signal line isconnected with the counter electrodes in the inside of the first pixels,the first pixels only are associated with one of the narrow portions ofthe drain signal line and the second pixels only are associated with oneof the wide portions of the drain signal line; the counter electrodes ofthe first pixels and the counter electrodes of the second pixels areelectrically connected with each other using conductive layers which areformed in a state that the conductive layers stride over the gate signallines, and wherein a substantial portion of the drain signal line of thesecond pixels is the wide portion, a substantial portion of the drainsignal of the first pixels is the narrow portion, the width of the wideportion is wider than the width of the narrow portion, and the wideportion of the drain signal line of the second pixels is formed at theposition that does not overlap the gate signal line.
 2. A liquid crystaldisplay device according to claim 1, wherein the first pixels and thesecond pixels are alternately arranged in the second direction.
 3. Aliquid crystal display device according to claim 1, wherein theextending direction of the pixel electrodes or slits formed in the pixelelectrodes assumes the direction which makes an acute angle with respectto the gate signal lines.
 4. A liquid crystal display device accordingto claim 1, wherein the number of pixel electrodes in the first pixel orthe number of slits formed in the pixel electrode is smaller than thenumber of pixel electrodes in the second pixel or the number of slitsformed in the pixel electrode.
 5. A liquid crystal display deviceaccording to claim 1, wherein the polarity of a drain signal supplied tothe drain signal lines differs between a range from the first pixel to aportion of the second pixel immediately before the next first pixel anda range from the next first pixel to a portion of the second pixelimmediately before the still next first pixel.